Thousands of children risk being consigned to educational failure because of
Ofsted demands to set pupils by ability in secondary school, teachers’
leaders have warned.

A move to scrap mixed-ability groups in favour of low and high sets will have a “negative impact” on standards across the board, it is claimed.

The Association of Teachers and Lecturers said that setting and streaming resulted in a slight improvement for the top set but any gain was more than outweighed by declines in results achieved by traditionally middle- and low-achieving pupils.

The comments will fuel the debate over the value of teaching children separately according to their prior attainment in academic subjects.

It came as teaching unions bitterly rejected the conclusions of a major Ofsted report that claimed large numbers of bright pupils were being systematically failed by state comprehensives.

In a report, the watchdog claimed that clever children were well taught in just a fifth of mixed-ability lessons, often receiving “mediocre” exercises and “insufficiently challenging” homework tasks.

At least a third of schools now use mixed-ability groups for the majority of lessons aimed at 11- to 14-year-olds, with other schools employing them for some subjects, it emerged.

But Sir Michael Wilshaw, the chief inspector, said he was strongly in favour of setting by ability in most classes from the age of 11 onwards.

Supporters of the approach claim that it allows the brightest children to progress at their own pace while allowing those at the bottom of the ability range to get specialist help to catch up.

But the report was attacked by teachers’ leaders, who claimed it was “absolutely wrong” to suggest that secondary schools failed to set high expectations.

Mary Bousted, general secretary of ATL, said that a move to scrap mixed-ability classes was contradicted by recent research on the subject.

One study by the Department for Education showed that setting in maths had a “negative effect on both attainment and motivation”, she said.

A separate study showed “that while there may be slight improvement in attainment for pupils in the top ability group, this is significantly outweighed by the negative impact on the rest of the class”, she added.

However, a study published last year by the Royal Economic Society showed that a higher proportion of “low-achieving pupils” in each class had a “negative and significant effect on the academic achievements of regular pupils” because they monopolised teachers’ attention.

Sir Michael said: “Unless you have well-qualified, experienced people who know how to deal with mixed ability then it doesn’t work. And if that’s not happening, it is much better to move towards a setting system.”

But Brian Lightman, general secretary of the Association of School and College Leaders, said: “This is too important an issue to be reduced to sweeping generalisations.

“We know there are some schools that should be doing more, but to suggest that a culture of low expectations is rampant in our schools is absolutely wrong.

“The majority of schools have good strategies in place to stretch all pupils.”